Membrane potential

High temperature proton exchange membrane fuel cells (HT-PEMFCs) are a promising clean technology, especially for automobile applications.1 These devices generate electricity from the chemical reactions that occur in the anode side of the cell, using H2 as a fuel and generating heat and water as by-products.2, 3 However, experimental studies using HT-PEMFCs show that degradation of the cell can occur after certain hours of operation (around 500 hours).4 Some of the factors that contribute to the…

A catalyst layer is usually the slimmest layer in a PEM fuel cell; however this is an extremely complex component because of its porosity, several phases, and reactions (Spiegel 2008). An efficient catalyst layer should provide several functions at the same time; transporting the electron and the proton, supplying oxygen and hydrogen and water management. The structure and composition of the catalyst layer affects all these roles. Optimization of the catalyst layer can provide for all these…

movement of sodium ions through these channels which affect action potential generation in nerves which is why Dr. Westwood experienced numbness after eating the puffer fish. Tetrodotoxin affects all excitable tissues, nerves and muscle, by binding to the sodium ion channels and preventing sodium to get into the cell. This will affect conductivity of nerve and prevent action potential from traveling down the axon. Without action potential reaching the neuromuscular junction no neurotransmitters…

polyspermy. As the sperm enters, the membrane potential immediately changes within a tenth of a second. Normally, the membrane potential of the egg is -70 mV, which allows the entry of sperm. Within seconds after sperm entry, the potential becomes positive. This happens because Na+…

large organelle which is surrounded by a nuclear envelope consisting of a double membrane, which contains many pores .However; pores allow substances, such as RNA, to move between the cytoplasm and the nucleus. Also, the nucleus contains chromatin which is made up of proteins and DNA (deoxyribonucleic acid) which controls the cells activity. Mitochondria The mitochondrion has an oval shape, and is a doubled membrane where the inner is folded to form cristae; its function is to increase surface…

Muscle contraction is made possible when an action potential is propagated from a motor neuron to a muscle fiber. This occurs at the neuromuscular junction, where the neuron innervates the muscle fiber. One nerve can innervate thousands of muscle fibers, allowing for an entire muscle to contract. At each neuromuscular junction, muscle tissue (an excitable tissue) is able to receive an electrical signal from the motor neuron and propagate it further. As the electrical signal reaches the terminal…

that alter voltages due to the action potential (EMG) promulgating from within neurons, to a muscle cell.…

which open when the action potential is initiated. With sodium ions flowing in, this causes depolarization, the inside becoming more negative. (Heymen, 2013) 6. What would happen to a neuron if it was exposed to tetrodotoxin? Be specific regarding its effect on the ability of a neuron to communicate. The tetrodotoxin causes the neuron to have an inability to communicate. This occurs because it prevents the sodium from moving into the cell and preventing the action potential from initiating.…

semipermeable membrane while osmosis of water is the movement of water through a semipermeable membrane from an area of high water potential (low solute potential) to an area of low water potential (high solute potential). Both diffusion and osmosis move in the direction that would create equilibrium on both sides of the semipermeable membrane. Equilibrium is reached when there is an equal concentration of solute and solvent on both sides of the semipermeable membrane. A semipermeable membrane…

diffusion in a model membrane system and the effect of solute concentration on water potential, the force created by both physical pressure and solute concentration, as it relates to living plant tissues. Diffusion is the passive movement of molecules or particles from a region of high concentration to an area of low concentration. Particularly, osmosis, a special type of diffusion, is the diffusion of a solvent, usually water molecules, through a semi permeable membrane, which is a membrane…